1

Figure 33. Recommended application circuit (Single Supply) with desaturation detection and active Miller Clamp

Description of Operation

Normal Operation

the IGBT collector-to-emitter voltage being monitored

Fault Condition

The DESAT pin monitors the IGBT Vce voltage. When the

voltage on the DESAT pin exceeds 6.5 V while the IGBT is

on, VOUT is slowly brought low in order to“softly”turn-off

the IGBT and prevent large di/dt induced voltages. Also

Figure 34. Fault Timing diagramactivated is an internal

feedback channel which brings the FAULT output low for

the purpose of notifying the micro-controller of the fault

condition.

Fault Reset

Once fault is detected, the output will be muted for 5 μs

(minimum). All input LED signals will be ignored during

the mute period to allow the driver to completely soft

shut-down the IGBT. The fault mechanism can be reset by

the next LED turn-on after the 5us (minimum) mute time.

See Figure 34.

+_

+_

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

DESAT

FAULT

CATHODE

ANODE

ANODE

CATHODE

+_

100 Ω

Q1

Q2

+

-

R

+ HVDC

- HVDC

3-PHASE

AC

+

-

0.1µF 0.1µF

0.1µF

7

+_

-

Figure 34. Fault Timing diagram

FAULT

6.5V

50%

10%

90%

50%

50%

Reset done

during the

next LED

turn-on

FAULT

FAULT

6.5V

50%

10%

90%

50%

50%

Reset done

during the

next LED

turn-on